Power supply devices such as a DC-DC converter and a charging device provided therewith have been used, for example, in hybrid cars and electric cars. Such power supply devices include a transformer, a choke coil, a primary semiconductor component, and a secondary semiconductor component. Patent Literature 1 discloses a power supply device in which two stacking bodies are formed by stacking the plurality of electronic components respectively into pairs. With this, downsizing and noise reduction of the power supply device are achieved.